China CNC Processing: Fast Online Quotation

An online quotation system is fast because it asks for the same few things our estimators ask for. A 3D model in STEP or IGES format, a 2D drawing if the part has tolerances or threads that are not modeled, the material grade, the quantity, and the surface finish. Send those five items and the quote is arithmetic plus process planning, not guesswork.

Files matter more than words. A STEP file with no drawing forces us to assume general tolerances, which are looser than most engineers expect. Suppose a bore needs ±0.005 mm or a face needs Ra 0.8–1.6 μm. That belongs on a drawing. One extra sheet of paper often changes the price more than a change of supplier does.

Quantity drives the process choice. One bracket is milled from bar stock or plate on a three-axis machine. Two thousand brackets may move to a dedicated fixture, a four-axis tombstone, or die casting. Tell us the annual volume as well as the first order, because the right process for 50 pieces is rarely the right one for 5,000.

If your part is under NDA, upload it anyway. Files are stored on access-controlled servers, and we can sign your NDA or return ours before any drawing is opened. Nothing about a fast quote requires you to expose design intent you would rather keep internal.

Every quote from our Dongguan plant includes a free DFM analysis, returned with the price inside 12 hours. It is a short list, not a redesign: wall thickness that will chatter, a pocket too deep for the tool diameter, a thread that needs a specific tap drill, a tolerance that cannot be held on the quoted setup.

Most flags are about tool access. A 0.8 mm deep slot with a 0.4 mm corner radius needs a 0.8 mm cutter, which will deflect unless we slow down and take light passes. We will quote it either way, but the note tells you the cost of that corner. Change it to 1.5 mm and the price often drops by a visible margin.

Tolerance stacking is the second common flag. A stack of five ±0.05 mm features can land outside ±0.005 mm overall. We point out where to control the datum and where the tolerance is free. That conversation usually happens before the first chip, which is cheaper for both sides.

We flag the process too. A part with deep bores and a turned outside face may run better on a mill-turn center than as two operations. That is not a sales line; it is the difference between two setups and one, and it shows up in the quoted hours.

Aluminium is the default for prototypes and light production. Grades 6061 and 6061-T6 machine cleanly at high spindle speeds and hold tight tolerances without stress relief. Grade 7075 is stronger but gummier; it needs sharper tools and a slower feed, and thin walls will move after machining. For housings, 6082 and 6063 give better anodizing results than 7075.

Stainless is where quotes spread out. Grade 303 cuts freely and suits high-volume turned parts. Grade 304 and 316 work-harden, so a light finishing pass that rubs instead of cuts will raise the price fast. Grade 17-4PH (SUS630) is common in aerospace and medical work; it machines well in the annealed state and gains strength after heat treatment, which we schedule as a separate step.

Titanium and nickel alloys run at low surface speeds. TC4 (Ti-6Al-4V) needs rigid setups and generous coolant, and a part that takes 20 minutes in aluminium may take two hours. Inconel is slower again. We quote these as their own line item so you can see the real cost before committing.

Plastics behave differently. POM and PEEK hold tolerance well; ABS and PP deflect under clamping pressure, so we use soft jaws and light cuts. Carbon fibre needs diamond-coated tooling and dust control. Tell us the service temperature and whether the part will be sterilized, because that decides between PEEK, POM and PC.

A quotation and free DFM analysis come back within 12 hours. That is a full working shift for an estimator to open the model, pick a process, and check tooling against our machine list. It is not an automated number from a formula.

Production can start within 24 hours of a released order. Raw material is the usual constraint: 6061 plate and 303 bar sit in stock, while a specific titanium grade or a large 7075 block may need a day to arrive. Parts ship in 3–5 days for standard jobs. Historical late-delivery probability at our plants is below 2%.

Three wholly-owned plants and 127 high-precision CNC machines, including 16 simultaneous 5-axis machining centers, mean a job does not wait for a machine to free up. When a five-axis center is busy, a quote can move to a mill-turn center without changing the drawing or the inspection plan.

Complex geometry is where five-axis earns its place. Adding rotation around the part lets a single setup reach undercuts, compound angles and deep pockets that would need three or four fixturings on a three-axis machine. Each refixturing adds setup time and a new chance for position error.